CVE-2026-109744 Other issue in the DOM: File component
A cross-site scripting vulnerability in the DOM File component allows attackers to inject malicious scripts, potentially leading to code execution or data theft.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-109744?
CVE-2026-109744 is a high-severity cross-site scripting vulnerability in Mozilla Firefox, published on 13 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Other issue in the DOM: File component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
Weakness: CWE-79
Which versions are affected by CVE-2026-109744?
How do I fix CVE-2026-109744?
Upgrade to a fixed version.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-109744 being exploited?
There is no known exploitation of CVE-2026-109744 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-109744, GHSA-5322-hggj-fqwc, UBUNTU-CVE-2026-109744.